From 6e723d2ab70678c1092ae2ba8d8dc2f4d8017262 Mon Sep 17 00:00:00 2001
From: josibake <josibake@protonmail.com>
Date: Tue, 16 Jul 2024 17:42:32 +0200
Subject: [PATCH] tests: add tests for KeyPair

Reuse existing BIP340 tests, as there should be
no behavior change between the two
---
 src/test/key_tests.cpp | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/src/test/key_tests.cpp b/src/test/key_tests.cpp
index 13dde7673b6d6..dc7a718c37fbc 100644
--- a/src/test/key_tests.cpp
+++ b/src/test/key_tests.cpp
@@ -13,6 +13,7 @@
 #include <uint256.h>
 #include <util/strencodings.h>
 #include <util/string.h>
+#include <secp256k1_extrakeys.h>
 
 #include <string>
 #include <vector>
@@ -299,6 +300,13 @@ BOOST_AUTO_TEST_CASE(bip340_test_vectors)
         // Verify those signatures for good measure.
         BOOST_CHECK(pubkey.VerifySchnorr(msg256, sig64));
 
+        // Repeat the same check, but use the KeyPair directly without any merkle tweak
+        KeyPair keypair = key.ComputeKeyPair(/*merkle_root=*/nullptr);
+        bool kp_ok = keypair.SignSchnorr(msg256, sig64, aux256);
+        BOOST_CHECK(kp_ok);
+        BOOST_CHECK(pubkey.VerifySchnorr(msg256, sig64));
+        BOOST_CHECK(std::vector<unsigned char>(sig64, sig64 + 64) == sig);
+
         // Do 10 iterations where we sign with a random Merkle root to tweak,
         // and compare against the resulting tweaked keys, with random aux.
         // In iteration i=0 we tweak with empty Merkle tree.
@@ -312,6 +320,12 @@ BOOST_AUTO_TEST_CASE(bip340_test_vectors)
             bool ok = key.SignSchnorr(msg256, sig64, &merkle_root, aux256);
             BOOST_CHECK(ok);
             BOOST_CHECK(tweaked_key.VerifySchnorr(msg256, sig64));
+
+            // Repeat the same check, but use the KeyPair class directly
+            KeyPair keypair = key.ComputeKeyPair(&merkle_root);
+            bool kp_ok = keypair.SignSchnorr(msg256, sig64, aux256);
+            BOOST_CHECK(kp_ok);
+            BOOST_CHECK(tweaked_key.VerifySchnorr(msg256, sig64));
         }
     }
 }